When a hinge is mounted to objects to be hinged with respect to each other, care must be taken to ensure proper alignment and mounting of the hinge and hinged objects. Doors that are in need of repair are often retrofitted with various types of hinges that are known for their increased strength among other factors. Hinges that are applied in the field are often installed under less than ideal conditions. To complete a quality field installation of a door, for example, the door must be maintained in proper alignment with the frame, requiring a prescribed set of clearances at each side of the door and at its top and bottom edges. If this is not done, the door may potentially rub against the frame or drag on the threshold, increasing the difficulty for persons entering or leaving the building as well as imposing additional stress and wear on all of the door hardware, such as locksets and automatic door closers.
Uniform industry standards for the design of butt hinges have been applied to doors and frames in the form of cutouts, or receiving mortises, that allow butt hinges to be fastened directly into these recesses. However, not all of the door alignment requirements are assured when the doors and frames are manufactured. Sometimes, particularly if the doors and frames arrive at the job site from different manufacturing sources, the cutouts or recesses may not correspond, creating misalignment problems that can affect the operating clearances. Also, the installation of frames can be affected by improperly dimensioned or misaligned wall openings, resulting in frame distortion that contribute to door misalignment. To install continuous hinges such as disclosed in my U.S. Pat. Nos. 3,092,870; 3,402,422; 4,976,008; 4,996,739; 4,999,878; 4,999,879; 4,999,880; 5,001,810; 5,201,902; 5,778,491 and 5,991,975, especially those types that are applied to the exterior faces of doors and frames when they are in need of hinge replacement, the installer typically must carefully remove the damaged hinges and mark and drill for the new fastener locations on both the door and the frame as best he can. All too often, when transferring the new screw hole locations from the continuous hinge to the door and frame, the hinge can shift, or the drill point can slide from the mark, contributing to poor door alignment when the installation is complete. Such fastener hole misplacements occur with even greater frequency when large holes are required for through-bolting, especially when hidden internal door reinforcements are encountered by the installer.
U.S. Pat. No. 1,346,029 teaches a butt hinge intended to be quickly and accurately hung. The hinge has channel portions which attach to a door with barbs and screws. Swinger members can be slid on or off the base plates for quick assembly and removal.
Also, it is often desirable that a continuous hinge match the door height so that resistance to the various forces acting on the door will be enhanced. Also, the sealing against the penetration of light, sound, and weather through the hinged edge of the door can be optimized when the hinge length is approximately equal to the door height. A wide variety of door heights exists, however. For instance, minimum residential door heights are typically 6′-8″, while doors for commercial and institutional applications are commonly 7′ or larger. It has been traditionally difficult to manufacture, handle, and store the many hinge lengths required to properly fit a variety of doors designed for architectural use.
Continuous hinges for these applications are subject to damage within the manufacturing environment because of the length and fragility of their component parts and because of consequential damage to the completed assembly during the various stages of shipment and transportation from the manufacturing site through the complex channels of distribution to the point of installation. Packaging, shipping, and shipping damage costs can become high because of the unusual ratio of length-to-girth or width of the package and the stringent requirements for protection against bending. In addition, the inventory storage requirements for these long and fragile hardware items are costly, because they require specialized shelving or racks at every intermediate location.
Costs are also present for obtaining and preserving the long lengths of the required hinge components before the assembly process can begin. The generation of manufacturing-scrap is increased at every stage if a part is dropped, twisted or bent, or if a fabrication or finishing defect appears within its length at any point in the manufacturing sequence. Unlike conventional butt hinges, which are comprised of smaller, easier to handle and cheaper parts, any such defect reduces or destroys the value of an inherently long continuous hinge part which can add substantially to the overall cost of manufacture. While continuous hinges for very tall doors have sometimes been pieced together to form assemblies that are longer than any practical manufactured length, little attention has been paid to properly aligning these segments during installation so that the segments simulate the function of a single hinge.
Further complexity and cost results from the difficulty of maintaining adequate inventory of each and every required length suitable to the variety of door heights used in the construction industry. While it is possible to manufacture continuous hinges in virtually any reasonable length for large orders, the availability of unusual custom lengths is often subject to long delays and high costs at each step of the manufacturing and distribution cycle. The retrofit and door repair industry, which is a very large portion of the market for continuous hinges, is typified by its requirement for the immediate availability of an enormous variety of models and lengths so that schools, hospitals, shopping malls and other commercial locations can have their doors quickly restored to proper operation for reasons of traffic flow, safety, and security.
Also, one of the more difficult steps in continuous hinge installation in the field is the proper marking and preparation of the fastener holes in a way which will insure the alignment of the door to its frame when the installation is complete. Currently, the installation of continuous hinges is dependent upon the skills of the individual installer. While individual butt or mortise hinges are typically fitted into cutouts with pre-threaded bolt holes prepared in both the door and the frame at their respective factories, continuous hinges are more frequently applied to the unprepared surfaces of doors and frames which offer little to assist in their alignment. Repair work in particular, where continuous hinges are used to overcome conditions in which conventional hinges have failed, is more dependent upon the skill level of the installer because the working environment as well as the condition of the door and frame components may be less than ideal, largely because the doors themselves may have suffered damage when their hinges failed and because the work must often be completed very quickly with a minimum of installation tools. Unless all of the fastener locations for a continuous hinge are carefully marked and drilled, the door will interfere with or rub against the frame following installation or shortly thereafter.